1. Field of the Invention
The present invention relates to a moving fluid energy recovery system for use in connection with generating electricity through rotational motion produced by moving fluid either by weather or a vehicle in motion.
2. Description of the Prior Art
Moving fluid energy recovery systems are desirable for transferring kinetic energy of a moving fluid to rotational motion for driving an electric generator or alternator. It can be appreciated that a fluid energy recovery system that is inexpensive and simple to manufacture is very beneficial to the production of electricity. These systems can be easily purchased, installed and maintained by the average person.
The ever increasing price of oil and gasoline, and the increasing global demand for electricity, in concert with the lack of natural resources to keep up with growing demand, has provided new impetus to look toward the development of alternative and renewable energy sources.
The use of fluid driven rotors or vehicle mounted wind powered electric generators are known in the prior art. Some of these known devices are complex and difficult to manufacture. While these systems and devices fulfill their respective, particular objectives and requirements, the aforementioned patents do not describe a moving fluid energy recovery system that allows generating electricity through rotational motion produced by moving fluid. But these, and similar, efforts have not been successful in overcoming the problems associated with the prior known wind or water machines. As a consequence, wind or water machines have not been commercially attractive and have not achieved substantial acceptance in the marketplace.
The windmill construction which has been most commonly utilized for the generation of electricity is a plural-bladed propeller positioned vertically for rotation about a horizontal axis. This type of construction has been widely used because, when positioned into the wind, the entire surface of each blade of the propeller is exposed to the full force of the moving air. The commercial windmill industry has developed around the horizontal-axis construction and the aerodynamic principles and knowledge discovered in connection with atmospheric flight. Accordingly, it has become common practice to design such machines for the atmospheric/wind conditions of specific locations by varying the number and/or dimensions of the blades employed. The fewer the propeller blades, the more efficient the machines become at high wind speeds but the less efficient they are at lower wind speeds. Furthermore, it is not practical to position the windmill on a moving vehicle.
Because the blades of horizontal-axis windmills are coupled indirectly to an electric generator which is effective only at a constant design speed, and because the blades themselves become unsafe at high speeds, the horizontal-axis windmills have been capable of utilizing only a small percentage of the theoretically-available power in the wind. The multi-blade windmills have high starting torque at low wind speeds, harvesting up to 30% of the kinetic energy from the wind but become very inefficient at high wind speeds. The most common and efficient windmills today are of the two and three blade types designed for high tip speed operation. These machines harvest roughly 42% of the theoretical 59.2% kinetic energy from the wind. Such windmills operate within a narrow window or range of wind velocities defined by a cut-in wind speed of 3-5 mps (meters/sec.) and a cut-out wind speed of about 25 mps. To maintain a near constant level of torque to drive the generator has required either: complex controls, in the case of pitch control, or intricate blade designs, in the case of stall control, both of which are expensive to build and maintain. In addition, such wind machines require yaw mechanisms with motors, gearboxes, cable twist counters, etc. to keep the machine yawed against the wind. These requirements have combined to make windmills economically unattractive except in areas where alternative forms of electricity generation are not readily available.
The windmill designs of the prior art also have other drawbacks. They have problems with gyroscopic vibration when the machine veers with changing wind direction. They are vulnerable to high bending moments at the base or root of the blades as each blade passes by or into the wind-shade of the supporting mast as well as when being braked during tempest conditions. These bending moments lead to frequent blade replacements and high maintenance costs. Because of their massive structures, these machines, of necessity, are remotely located miles from the area of power usage, thus necessitating construction of expensive power grids to transport the energy produced to the point of consumption, (generally large cities). Consequently, an approximate eight to ten percent of the power generated never reaches its destination due to line and transformer losses. Lastly, because of opposition from environmentalists with regard to the esthetics in natural settings as well as prohibition from municipal regulating authorities due to safety hazards associated with these large-prop machines in populated areas, many areas which would be ideal for generating wind energy, such as atop large buildings, are simply off-limits due to opposing design constraints.
Additionally, vehicle attached power generation devices are also known in the prior art. These devices typically use a variation of a squirrel-cage system to replace the windmill. The rotating cage of these devices uses movable deflectors to guide the wind into the cage where a single set of arcuate blades drives a generator. These known systems are complex, with control systems and inefficient rotor designs, thereby not making them practical to be placed and integrated into a moving vehicle.
Therefore, a need exists for a new and improved moving fluid energy recovery system that can be used for generating electricity through rotational motion produced by moving fluid. In this regard, the present invention substantially fulfills this need. In this respect, the moving fluid energy recovery system according to the present invention substantially departs from the conventional concepts and designs of the prior art, and in doing so provides an apparatus primarily developed for the purpose of generating electricity through rotational motion produced by moving fluid.